All posts for the month January, 2016

I recently read a very interesting opinion piece: asking students to write a math autobiography as the first assignment of the semester. I may try this out in a future semester. From the opinion piece:

Want to know one of my favorite assignments that I have ever given my students? Want to know learn a lot of useful information about your students in a short amount of time?

I know it sounds too good to be true, but this one simple assignment could change how you teach your classes and how well you know your audience…

Math Autobiography

Purpose of the Assignment
As your instructor, I want to get to know you as a person and as a student of mathematics. This will help me better meet your needs. It also helps our department as we work to improve our services to students.

Content
Your autobiography should address the four sections listed below. I’ve listed some questions to help guide you, but please don’t just go through and answer each question separately. The questions are just to help get you thinking. Remember the purpose of the paper. Write about the things that will give me a picture of you. The key to writing a good piece is to give lots of detail…

Section 1: Introduction

How would you describe yourself?

Where are you from? How did you decide to attend Fort Lewis?

What is your educational background? Did you just graduate from high school? Have you been out of school for a few years? If so, what have you been doing since then?

General interests: favorite subjects in school, favorite activities or hobbies.

Section 2: Experience with Math

What math classes have you taken and when?

What have your experiences in math classes been like?

How do you feel about math?

In what ways have you used math outside of school?

Section 3: Learning Styles and Habits (specifically for math)

Do you learn best from reading, listening or doing?

Do you prefer to work alone or in groups?

What do you do when you get “stuck”?

Do you ask for help? From whom?

Describe some of your study habits. For example: Do you take notes? Are they helpful? Are you organized? Do you procrastinate? Do you read the text?

Section 4: The Future

What are your expectations for this course?

What are your responsibilities as a student in this course? What do you expect from your instructor?

What are your educational and life goals?

How does this course fit into your educational goals?

The author’s conclusions:

It was fantastic! Students took it way more seriously than I could have imagined. Some wrote pages and all wrote enough to get to know them. It made me realize that we don’t give our students opportunities to share their math baggage/backgrounds/etc. with us often enough. Students shared everything from horror stories about being shamed in math courses to their excitement about math. Some let you know what they have heard about your class and even fears they may have such as a fear of presenting or working with others.

In 2015, Urschel played in the NFL playoffs for the Ravens while simultaneously (pdf) working on a paper on graph eigenfunctions. (What have you done lately?) The paper, entitled, “A Cascadic Multigrid Algorithm for Computing the Fielder Vector of Graph Laplacians,” is available online.

Suppose we have data set with points. We want to perform a linear regression, but first we sort the values and the values independently of each other, forming data set . Is there any meaningful interpretation of the regression on the new data set? Does this have a name?

I imagine this is a silly question so I apologize, I’m not formally trained in stats. In my mind this completely destroys our data and the regression is meaningless. But my manager says he gets “better regressions most of the time” when he does this (here “better” means more predictive). I have a feeling he is deceiving himself.

The answers were priceless:

Your intuition is correct: the independently sorted data have no reliable meaning because the inputs and outputs are being randomly mapped to one another rather than what the observed relationship was.

There is a (good) chance that the regression on the sorted data will look nice, but it is meaningless in context.

And:

If you want to convince your boss, you can show what is happening with simulated, random, independent x,y data. With R:

And:

This technique is actually amazing. I’m finding all sorts of relationships that I never suspected. For instance, I would have not have suspected that the numbers that show up in Powerball lottery, which it is CLAIMED are random, actually are highly correlated with the opening price of Apple stock on the same day! Folks, I think we’re about to cash in big time. 🙂

The sad end of the story, from the original poster:

Thank you for all of your nice and patient examples. I showed him the examples by @RUser4512 and @gung and he remains staunch. He’s becoming irritated and I’m becoming exhausted. I feel crestfallen. I want my work to mean something. I will probably begin looking for other jobs soon.

Today is one of the high points of the American sports calendar: the AFC and NFC championship games to determine who plays in the Super Bowl.

A major pet peeve of mine while watching sports on TV: football announcers who “explain” that a receiver made a great reception because “he caught the ball at its highest point.”

Ignoring the effects of air resistance, the trajectory of a thrown football is parabolic, and the ball is the essentially the same height above the ground when it is either thrown or caught. (Yes, there might be a difference of at most three feet, but that’s negligible compared to the distance that a football is typically thrown.) Therefore, a football reaches the highest point of its trajectory approximately halfway between the quarterback and the receiver.

And anyone who can catch the ball that far above the ground should be immediately tested for steroids.

The Mathematical Association of America recently published a number of promotional videos showing various mathematics can be used in “the real world.” Here’s the third pair of videos describing how mathematics is used for certain problems in materials science. From the YouTube descriptions:

Dr. Sumanth Swaminathan of W. L. Gore & Associates talks about his career path and the research questions about filtration that he considers. He works to understand the different waste capture mechanisms of filtration devices and to mathematically optimize the microstructure to create better filters.

Prof. Louis Rossi of the Department of Mathematical Sciences of the University of Delaware presents two introductory mathematical models that one can use to understand and characterize filters and the filtration processes.